In order to effectively treat a localized area of body tissue, a therapeutic agent may need to be maintained at the treatment site for an effective period of time. Problems arise, however, when therapeutic agents need to be applied to a site that is covered by or constantly exposed to body fluids. Such fluids tend to rapidly wash away the therapeutic agents. For example, when therapeutic agents are applied to the buccal cavity, saliva production and natural replacement of the mucosal tissue limit the effectiveness and residence time of therapeutic agents. Additionally, therapeutic agents introduced to a body lumen, such as an artery, can be swept downstream by blood flow.
In order to address the specific environment of certain body tissues, medical devices with bioadhesive properties have been created to treat wounds and deliver therapeutic agents to such body tissues. Bioadhesion refers to the ability of certain materials such as, polymers, macromolecules and hydrocolloids to adhere to biological or body tissue. Bioadhesion is a complex phenomenon, depending in part upon the properties of the bioadhesive materials, the treatment site and the environment surrounding the treatment site. Several factors have been found to contribute to the bioadhesive capability of polymers including the molecular weight of the polymer, the presence of functional groups and anionic charges, the strength of anionic charges and the ability of the polymer chains to interpenetrate the mucous layer.
In the past, bioadhesive materials have commonly been used in dentistry, orthopedics, ophthalmology, and in surgical applications. Recently, bioadhesive materials have been used in other areas such as soft tissue-based artificial replacements, and controlled release systems for local release of therapeutic agents to deliver therapeutic agents to the nasal cavity or intestines.
As medical procedures become more specialized, the need for bioadhesive materials that offer a high degree of control and accuracy increases. In order to better control such bioadhesive materials, the bioadhesive properties of the bioadhesive material should be able to be switched on and off as needed. Accordingly, there is a need for improved bioadhesive materials that can offer the user increased control of the bioadhesive properties and greater accuracy during the application of the system to the treatment site.